Suspension polymers based on methyl methacrylate

US5300601A · kind A · utility

Assignee

• BASF SE

Inventors

• Siegmund Besecke · Hameln, DE
• Wilfried Schoen · Ingelheim am Rhein, DE
• Karl-Ludwig Endlich · Mainz, DE

Key dates

• Filing date: Dec 2, 1991
• Grant date: Apr 5, 1994
• Expiry date: Dec 2, 2011

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C08F20/14
• WIPO field: Macromolecular chemistry, polymers
• WIPO sector: Chemistry

Abstract

Suspension polymers of PA0 a) from 80 to 100% by weight of methyl methacrylate and PA0 b) from 0 to 20% by weight of further monomers capable of undergoing free radical polymerization, are obtainable by polymerization at a temperature of from 100.degree. to 140.degree. C. which is virtually constant over the major part of the polymerization time by means of an initiator system consisting of two or more peroxide initiators I having different decomposition temperatures T at which in each case half of the initiator has decomposed after 1 hour, wherein PA1 the initiator I.sub.min having the lowest decomposition temperature has a decomposition temperature T.sub.min of from 60.degree. to 100.degree. C., PA1 the initiator I.sub.max having the highest decomposition temperature has a decomposition temperature T.sub.max of from 100.degree. to 140.degree. C., the difference between T.sub.max and T.sub.min is greater than 10.degree. C. and I.sub.max is a perketal of the general formula (1) ##STR1## where R.sup.1 and R.sup.2 are identical or different alkyl radicals of 1 to 5 carbon atoms and R.sup.1 and R.sup.2 may be bonded to form a 5-membered or 6-membered ring and R.sup.3 is tert-butyl or …